Want to ruin a perfectly a nice day at the office? Try to identify someone to pitch at the Susan Thompson Buffett Foundation.

The place is a case study in non-transparency, and it's super hard to even figure out who's doing the grantmaking. Which is crazy, because putting aside medical foundations that assist patients, STBF ranked number five in total giving in 2012, shelling out $367.1 million in 2012. That total put it well ahead of such brand name biggies as Robert Wood Johnson, Kellogg, Open Society Foundations, Mellon, and Packard.

For most grantseekers, trying to penetrate this place is like being a tourist asking around for the Mafia in Little Italy. The website is a laughable dead end, focusing only STBF's education giving while omitting huge key funding areas, and STBF's 990s lag maddeningly behind by a few years. If you try calling the foundation, you get a message saying that nobody is there and that they don't accept proposals, have funding guidelines, or publish an annual report (but at least you can leave a message!).

While you can understand why a foundation that is deeply enmeshed in protecting abortion rights might want to keep a low profile, this seems excessive.

We all know that STBF is moving big money in developing countries and also here in the United States. But to whom, and why, and through what grantmaking programs with what priorities run by what staff—all that is quite mysterious.

Until now.

Okay, I'm overpromising. But I'll do my best to shed some light on STBF by explaining who's giving out all that money. Once I'm done, I'll have written the longest article I know of about one of the biggest spending foundations in the world, which says something about the state of media coverage of philanthropy.

Warren Buffettestablished the foundation, originally named the Buffett Foundation, in the 1960s. It was renamed the Susan Thompson Buffett Foundation in honor of his wife after her death in 2004.

For a long time, the foundation gave away lots of money, but not compared to Buffett's fortune. Susan was the foundation's president, and Warren tended to stay out of things. The foundation focused mainly on the couple's shared concerns about reproductive rights and population control. Big gifts were made annually to a relatively small number of groups, including Planned Parenthood and International Projects Assistance Services.

Allen Greenberg, then married to the Buffetts' daughter Susan, was put in charge of the foundation's operations in 1987 and, for years, was the foundation's only employee. He still serves as executive director. More about him in a moment.

The foundation suddenly became a very big deal when Susan Buffett died and left it around $2.5 billion. Overnight, it joined the ranks of the top 25 or so foundations in the United States. It stepped up its giving dramatically.

And the foundation's assets are slated to keep growing, due to a planned infusion of Berkshire Hathaway shares from Warren worth several billion dollars over coming years. STBF could easily double in size.

Even as its giving expanded, though, the foundation has remained very much a family affair. Susan Buffett, or Susie, is the board chair. Peter Buffett is also on the board, or was as of 2012. Greenberg is still ED, as I said, and serves on the board, too, with a handful of other people.

Susie appears to be a driving force behind the foundation's giving, even as she also runs her own Sherwood Foundation. Susie is into lots of issues, both domestic and international. She's been deeply concerned about global development issues, and both she and her brother, Howard G. Buffett, are on the board of ONE, the global anti-poverty organization co-founded by Bono.

I can (and will) write a whole long post about Susie, who is a very low-profile funder. But suffice to say that she appears to be the most pivotal figure in the STBF universe.

Greenberg has really made the foundation his life's work, and there are no signs that's going to change as he approaches 60. For somebody overseeing such big giving, he keeps a remarkably low profile. You won't find any media interviews with him, or see him on panels at foundation conferences. As a result, it's hard to know what he thinks about anything.

What we do know about Greenberg is that he's a lawyer and used to work at Public Citizen, the progressive watchdog group founded by Ralph Nader. After moving to Omaha to run the foundation, Greenberg worked closely with Susan Thompson Buffett when she was alive, and earned the respect of the NGOs they were supporting in the family planning space.

The next two key figures at the foundation are Türkiz Gökgöl, who directs its international program, and Tracy Weitz, who directs the domestic program.

Gökgöl is incredibly low profile, given how much money STBF gives out internationally. (Notice a pattern here?) Again, no media interviews, no long bio on LinkedIn, no ubiquity on the conference circuit. Gökgöl is originally from Turkey, but earned her doctorate from Harvard University in 1979. She then became a professor before joining Pathfinder International in 1983 as its representative in Turkey. She stayed with that organization into the 1990s, becoming its vice president for Asia and Near East, and expanding the group's work on family planning and reproductive health into several new countries. She also did a stint at the UNFPA in the late 1990s running its operations in the former Soviet republics of Central Asia.

Coming back to Turkey, she started a reproductive rights organization called the Willows Foundation in late 1990s, and was involved in other Turkish groups as well, working in tough terrain to empower women. Presumably, this is how she hooked up with STBF, where she started working in 2005.

You won't find email addresses for any of the program officers on the foundation's website, but here's Gökgöl's: tgokgol@stbfoundation.org.

Tracy Weitz, on the domestic side of STBF, is brand new in this job—no press release, of course—which she took over from Judith De Sarno, a long time leader on reproductive rights issues.

Weitz is another impressive scholar-practitioner, with a PhD in medical sociology and a master's in public administration. She worked for Planned Parenthood early in her career, and she's worked squarely on abortion and women's health issues for many years at the University of California in San Francisco, where she's been affiliated since 2002. Her bio at USCF states:

Dr. Weitz's passion is for those aspects of women's health which are marginalized either for ideological reasons, or because the populations affected lack the means or mechanisms to have their concerns raised. Her current research focuses on innovative strategies to expand abortion provision in the U.S. Included in her research portfolio is a demonstration project of the use of nurse practitioners, certified nurse midwives, and physician assistants as providers of abortion care in California, several studies of abortion regulation, and a national strategic plan to secure access to later abortion care.

Sounds like the right person to be heading up STBF's domestic work, which has long taken the foundation into the heart of the abortion battle. Weitz's USCF email is is weitzt@obgyn.ucsf.edu. Her email at STBF, we presume, is tweitz@stbfoundation.org.

I could go further down the list of STBF staff, but this post is pretty long already. However, if search the foundation's name on LinkedIn, you'll find a bunch of them, including Stephen Heartwell, the deputy director of domestic programs (sheartwell@stbfoundation.org), program officers like Lindsey Barari and Karen Gluck (kgluck@stbfoundation.org), Kellie Pickett, Director of Scholarships (kpickett@stbfoundation.org), and others.

If you know anything about STBF, chime in below in the comments section and I'll build out this piece further.